This project is to investigate a novel composite cardiac patch consisting of stacked cell sheets and a thin layer of decellularized porcine myocardial scaffold for cardiac repair. Conventional cell therapy through direct cell injection is often associated with low retention and engraftment rate. In addition, dissociation of cells using proteolytic enzymes in the procedure disrupts the cell-cell and cell-extracellular matrix interactions and impacts cell functions such as survival, adhesion, proliferation and differentiation. We recently developed a novel thermo-responsive mechanism to efficiently generate cell sheets; the cell sheets offer unique features that retain the microenvironment of the cells by avoiding enzymatic treatment, and retaining cell-cell junctions and their deposited ECM. Because of these features, we propose that cell sheet transplantation will increase cell survival and improve engraftment of cells to the host tissue. However, limited mechanical strength of the layered sheets offers some challenges such as limited durability and even breakage, which would mitigate any mechanical support. Mounting evidence demonstrates the superior biological and mechanical properties of decellularized matrix as tissue engineering scaffold compared with other nature or synthetic biomaterials. Therefore, we hypothesize that a combination of cell sheet and acellular scaffold increases efficacy of stem cell delivery and engraftment, and provides mechanical compensation for the infarcted heart. Using our novel thermo-responsive surface, mesenchymal stem cell sheets will be harvested and seeded on a thin decellularized porcine myocardial scaffold. Their interactions will be examined in vitro and the variables affecting the interaction will be identified. The knowledge that we learn from these studies will be used to optimize the composite cardiac patch. In addition, mechanical and electrical stimulus will be explored to enhance the composite cardiac patch to achieve high cell viability and matching cardiac mechanical properties. The ultimate therapeutic effects of the composite cardiac patch will be determined using a rat model of myocardial infarction. Given the multidisciplinary nature of regenerative medicine, this work will bring together two laboratories specializing in cardiac tissue engineering and biomechanics. The supportive laboratory is also eligible for AREA (R15) support. This proposal meets the goals of the AREA program to support meritorious research and to strengthen the biomedical research environment at the University of Akron.